This document discusses inheritance and genetics through three subtopics: variation, what is inheritance, and genetics and society. It begins by defining what a species is and providing examples of species and their varieties. It then discusses Mendel's experiments with pea plants that discovered the basic principles of heredity and inheritance patterns. The document explains key genetics concepts like genes, alleles, dominant and recessive traits, phenotypes, genotypes, and uses Punnett squares and monohybrid crosses to demonstrate inheritance patterns.

1. INHERITANCE…

2. This unit consists of 3 sub-topics… VARIATION WHAT IS INHERITANCE GENETICS AND SOCIETY

3. SUB-TOPIC A… VARIATION.

6. Lemurs of Madagascar

7. Amazonian Frogs Can you think of some more examples ? Write them down !!

10. …Make mine a MULE What does ‘sterile’ mean ?

14. Environmental or Inherited?

15. How does variation come about? Sexual reproduction Genetic information exchanged by

18. Why aren’t fruits from the same plant identical ?

19. What about this wheat grown in the same field from the same parent plants ?

20. Why does one organism look different to another ? 1. Do the members of this family have any similar features ? 2. Are the members different in any ways ? 3. What reasons can you think of to explain these differences ?

26. Discontinuous variation

28. Continuous variation.

29. Inherited, environmental or both? I Eye colour I Blood group E Got a bad cold B Intelligence E Cut on face I Beard B Strength E Dyed blonde hair B Height B Weight I Sex Cause Example Cause Example

38. SUB TOPIC B – WHAT IS INHERITANCE ?

40. phenotypes These are things like eye colour, skin colour and hair colour. They are inherited.

51. Monohybrid inheritance of coat colour in mice

52. Various coat colours are found amongst mice. Two of these are black fur and brown fur. If a mouse has black fur, in this exercise its phenotype will be represented: If a mouse has brown fur, in this exercise its phenotype will be represented:

53. Consider the following cross. true-breeding true-breeding black mouse x black mouse Parents F 1 ? Do you think the F 1 will be all black offspring ? Do you think the F 1 will be all brown offspring ? Do you think the F 1 will be some black and some brown ?

54. 1..You are right. true-breeding true-breeding black mouse x black mouse Parents F 1 all black offspring A true-breeding black mouse crossed with another true-breeding black mouse can only produce more black mice.

55. 2 and 3…You are wrong. true-breeding true-breeding black mouse x black mouse Parents F 1 all black offspring A true-breeding black mouse crossed with another true-breeding black mouse cannot produce brown mice, only black mice.

56. Consider the following cross. true-breeding true-breeding brown mouse x brown mouse Parents F 1 ? 1.Do you think the F 1 will be all black offspring 2.Do you think the F 1 will be all brown offspring 3.Do you think the F 1 will be some black and some brown

57. 2…You are right. true-breeding true-breeding brown mouse x brown mouse Parents F 1 all brown offspring A true-breeding brown mouse crossed with another true-breeding brown mouse can only produce more brown mice.

58. 1 and 3…You are wrong. true-breeding true-breeding brown mouse x brown mouse Parents F 1 all brown offspring A true-breeding brown mouse crossed with another true-breeding brown mouse cannot produce black mice, only brown mice.

59. Consider the following cross. true-breeding true-breeding black mouse x brown mouse Parents F 1 ? 1.Do you think the F 1 will be all black offspring 2.Do you think the F 1 will be all brown offspring 3.Do you think the F 1 will be some black and some brown

60. 1…You are right. true-breeding true-breeding black mouse x brown mouse Parents F 1 all black offspring The genetic information for black coat colour masks the genetic information for brown coat colour.The black colour is dominant and the brown colour is recessive .

61. 2 and 3…You are wrong. true-breeding true-breeding black mouse x brown mouse Parents F 1 all black offspring The genetic information for black coat colour that comes from one parent dominates and masks the genetic information for brown coat colour that comes from the other parent. So all the F 1 mice in this cross are black .

65. Meiosis Cell division – ‘ reduction division’ (different from Mitosis) Production of sex cells called gametes containing HALF the normal number of chromosomes (HAPLOID)

67. zygote When a sperm and egg cell(Gametes) fuse together, they produce this. The full chromosome number is restored (46 or DIPLOID)

68. diploid We use this word to describe cells which contain the full complement of genetic material. In humans this would be 46 chromosomes (23 pairs)

69. mitosis Division of a cell to produce 2 daughter cells which each has the same number and kind of chromosomes as the mother cell

70. sexual reproduction Type of reproduction that involves fusion of gametes containing the HAPLOID (HALF) number of chromosomes. Why is this important ?

71. X Y X X X X Y X XX XY XX XY female male female male Parents Sex cells Offspring 50% of the offspring should be male and 50% should be female, eg a ratio of 1:1. female male Determination of gender:

77. Gene diagram – Flower colour Genotype of alleles- R = red flower r = yellow flower All genes occur in pairs – so 2 alleles affect a characteristic – possible combinations are; genotype RR R r rr Phenotype RED RED YELLOW

78. Gene diagram – Flower colour Male female RR rr parent gamete R R r r Offspring genotype Rr Rr Rr Rr Phenotype All red

79. Gene diagram – Flower colour Male female Rr Rr parent gamete R r R r Offspring genotype RR Rr Rr rr Phenotype Red yellow red red 3 red : 1 yellow

80. Gene diagram – Flower colour Male female Rr rr parent gamete R r r r Offspring genotype Rr Rr rr rr Phenotype Red yellow yellow red Red 50% yellow 50%

83. Ok… Lets look at it again

89. Harry Potter and the recessive allele How Are Wizards Made ?

93. The Malfoys Lucius Malfoy ( mm ) Narcissa Malfoy ( mm ) Draco Malfoy ( ) The Malfoys are a ‘pure blood’ family All their ancestors are wizards so they must have the alleles mm m m

94. Lily Potter ( mm ) James Potter ( mm ) Harry Potter ( WW ) Both Harry’s parents had magical ability so they must both have been mm They passed these alleles on to Harry The Potters m m

95. The Weasleys are pure blood wizards so they all have the alleles mm

96. Hermione is a powerful witch so she must be mm Both her parents are muggles so they must be Mm so they can give her a m allele each Mm Mm mm

97. Tom Riddle is a ‘half blood’. His mother was a witch (mm) and his father was a muggle His father must have had the alleles Mm so he could give him the other m allele mm Mm mm

98. Filch is a ‘squib’ Both his parents are mm so he should be too because he can’t get an M allele from either parent but he can’t do any magic This means he has a mutation so his wizarding powers don’t work or the man he thinks is his father isn’t really and his mother had an affair with a muggle !

99. What wizarding alleles would Ron and Hermione’s children have ? Ron (mm) Hermione (mm) Children ( ) m m

100. Their children could only get the m allele from both parents so they would all be wizards m m m m m m m m m m Hermione m m Ron

101. What wizarding alleles would Ginny and Dudley’s children have ? If Dudley is Mm Ginny mm Dudley Mm Children WW or mM m M m m

102. Half of their children would be likely to get the m allele from both parents so they would be wizards The other half would be likely to get an M allele from Dudley and would be muggles m m m m m M m M m m Ginny M m Dudley

103. What wizarding alleles would Ginny and Dudley’s children have ? If Dudley is MM Ginny mm Dudley MM Children WM m M

104. Their children would get the m allele from Ginny and the M allele from Dudley so they would all be muggles m M m M m M m M WM WM m WM WM m Ginny M M Dudley

105. What wizarding alleles would You expect Hermione’s brothers and sisters to have ?

106. The Granger’s children have a one in four chance of getting m alleles from both parents and having magical ability They also have a one in four chance of getting M alleles from both parents and being a muggle They could also get only one m from their mother or father and still be a muggle m M m M m m M M Now check your fact sheet.Make sure you have marked off ALL the boxes.Ask your teacher to go over any points you do not understand MM WM M WM WW m Mrs Granger M m Mr Granger

107. SUB-TOPIC C GENETICS AND SOCIETY

108. SELECTIVE BREEDING Look at the difference between these species of dog :

109. Wild dogs Terriers Collies Viemerana

111. Where have all these different species come from? All these species are related to the wolf. But how?

113. Selective Breeding is the gradual improvement of animal and plant characteristics over time, for man’s benefit. Select for breeding only those animals or plants with desirable characteristics

114. This artificial selection of characteristics happens in plants as well.. In the wild there are various species of corn plant

115. Good point: Strong stem Bad point: Small head Good point: Huge head of grain Bad point: Drought sensitive 1 2 3 4 Bad point: Small root Good point: strong roots Bad point: Small plant Good point: Disease resistant

116. Good point: Strong stem Good point: Huge head of grain Super CORN! Good point: Strong roots Good point: Disease resistant

117. Look what has happened to the varieties of the corn over last few hundred years.

118. Look at the variety of plants that have been artificially selected from mustard!

119. Growing lots of different varieties of wheat………… …… looking for new characteristics.

120. Things I must know about selective breeding(SB) is the gradual improvement of organisms characteristics – for humans benefit. takes hundreds of years We have lots of SB animals and plants SB animals & plants produced higher yields: 1. more milk 2. more meat 3. more fruit

121. MUTATIONS A mutation is a change in the structure and amount of an organism’s genetic material

123. Normal fly head This is a normal Fly’s head

124. Antennapedia fly Here,the legs replace the antennae on the head…a harmful mutation

132. Down’s Syndrome is the most common chromosomal abnormality. It occurs in 1:800 to 1000 live births. Look at the following example of a harmful mutation….

133. Cause 92% to 95% of all causes of Down’s Syndrome are attributable to an extra chromosome 21. Children with an extra chromosome 21 are born to parents of all ages but greater risk for women 35 years and older.

134. Intelligence This varies from severely retarded to low normal intelligence but is generally within the moderate range.

135. Social Development May be 2 to 3 years beyond the mental age, especially during early childhood.

136. Sensory Problems Strabismus, Myopia ,Hyperopia, excessive tears, head tilt, cataracts. Physical Disorders -Respiratory infections. Leukemia (is 10 to 30 times more frequent). Thyroid dysfunction.

137. How can we tell if a baby will have Down’s Syndrome ?

139. Does this baby have Down’s ..?